It seems to me that at some upgrade I’ve done recently (perhaps Mojave?) the Mail app now pops up when there is incoming mail. This happens even if the app is minimized.
The problem is that it is disruptive if I’m concentrating on something. But I don’t want to close the mail app – I just want the indicator on the icon to show that there are new messages.
So anyone know of the trick or setting to get the non-intrusive behavior back?
Notifications -> badges (yes) -> banners (no)
This works for my email…
Trying that out now. (Banners was on). Thanks!
Did anything work for you? I think I have the same issue, and I’ve found no solution (I just quit mail…).
To clarify, my issue is not notifications popping up, it is the whole app taking centre-stage, whether I have new mail or not. This is most annoying when I’m in full-screen and Mail decides to interrupt and put me in Split Screen mode!
JKoopmans suggestion worked for me. And, yes, the issue was the app itself popping up. But it isn’t doing it any more. I do get the badge and the beep, but those are fine (and desired).
Oh well, it doesn’t fix it for me.
I’m happy for you tho’ 
Unfortunately, it doesn’t work thoroughly. The window does open from minimized but doesn’t come to the foreground, so If I have a big foreground window I don’t see the mail window.
OK, I tracked down the real problem, at least for me. If there is an error accessing a mail server the window will pop open. One of the servers I use isn’t reliable. When it doesn’t respond the window pops open! Otherwise it stays minimized.
That appears to be the issue for me too. I’ have thought GMail, Outlook and Apple emails would be better, though.
Thank you.
Same issue. Seems to be GMail that is the problem.
I found a workaround for the initial problem (Mail pops up even if minimized when fetching mail). Pretty simple – create a new Space and put the mail app in that, window opened, or make it full screen (seems crazy on a 27" iMac display though).
It turns out that macOS will not change spaces to show the misbehaving Mail, so it no longer is a disturbance. Just a shame it took me half a year to solve this!
